Luminaire



| c. DOANE Dec. 24, 1940.

LUMINAIRE 2 Sheets-Sheet 1 Filed Dec. 29, 1938 INVENTOR [F1907 C. Don/vsATTORNEY Dec. 24, 1940.

L. C. DOANE LUMINAIRE Filed Dec. 29, 1958 2 Sheets-Sheet 2 1: TANC'E DISTANCE 2 6 o 6 [ILIFLIKW wwwwm WWQQZXU LQQK INVENTOR LEROY C. DOANEATTORNEY Patented Dec. 24, 1940 Leroy C; Duane, Merl-den, Conn.',assig'nor to The v Sight Light Corporation, Essex, Gonna .a :cor-'*poration of Connecticut 3 Application December 29, 19 38, Se'rialNol 12Claims. (01.240 73? The present invention relates to luminaires, and ismore particularly. directed toward luminaires for illuminating longnarrow areas.

The luminaire contemplated by the present invention is designed to beplaced below normal eye level and to concentrate the emitted flux into along narrow region below the luminaire. It is provided with a lightsource usually in the form of a lamp bulb, "an upwardly acting reflectorwhich intercepts downwardly directedlight and reflects it upwardly, anda downwardly acting opaque reflector close to the light sourceandextending laterally from the source to spread light reflected therebyto illuminate the remote areas. It is also provided with laterallyextending screens which depend from the laterally extending portionsofthe reflector to prevent spread of light laterally of the long narrowarea to "be 11- luminated. The construction just referred to is onewhich completely screens the light source at all normal angles ofobservation and lays down a generally rectangular pattern of light,

The luminaires contemplated by the present invention'areparticularlydesigned for illuminating the papers inoflice files. These files aregenerally about four feet high and the luminaire is designed so astobeplaced on topof the fileand to extend upwardly and outwardly so as to beabove Owing to the widelateral spread of light a'single luminaire sothat one can obtain symmetric ilcan build up the illumination on oneside at the expense of the illumination on the other side. Theaccompanying drawings show, for pur- 4 poses of illustrating the presentinvention, an embodiment in which the invention may take form, it beingunderstood that the drawings are i1- lustrative of the invention ratherthan limiting the same. Y i

In these drawings: Figure 1 is a diagrammaticelevational viewillustrating the luminaire placed on top! of a filing cabinet; 5

Figure 2 is an enlarged transverse sectional view through the luminaire;

Figure 3 is a top plan view of the luminaire withvparts broken away;

Figure 4 is a vertical cross sectional view taken on-the line 4-4 ofFigure 3;

Figure 5 is a fragmentary sectional view at an the drawers when thedrawers are pulled out.

lumination on opposite sidesof the luminaire, or

enlarged scale taken on the line 55 of Figure Figure 6 is,a fragmentaryview taken on the same plane as Figure 5 showing an arrangementofjparts, for securing a modified light distribution; a

Figure 7 is a chart indicating lightdistribution from the luminairelengthwise. of the area being illuminated; and

Figure 8 is a similar chartshowing light distribution tr'ansversely.' vi I The upper part of a filing cabinet is indicated in the drawings atIt and the luminaire L rests on'topv of the filing case. It hasaweighted base i I, and a tubular arm 12 through which the wiring iscarried. This" arm is bent soasto extend 'obliquely upwardly'andforwardly of the filing case as indicated. IThel'arm or tube [2 carriesa lamp'soc'ket 'l3,-.socket cover or husk I4 slitted adjacent its end'as indicated at I5,Figure 3.

The socket cover is adapted to telescopically receive alfitter i6 andthe parts can be clamped together' byfa band indicated at IT. The upperend of the fitter I6 supports a cup-shaped reflector I8 of suitable.size to permit inserting a. lamp bulb. IS; The light ,center O of thelamp bulb is vbelow the upper edge 20 of the reflector l8.- Thereflector l8 carries four spring elements indicated at 2 I. These may bemade in pairs'from a single 'strip of vmaterial as shown in thedrawings.

These spring elements haveiholes, such as indicated at 22, Figure 4, andare adapted to releasably' support the downwardly acting reflectingelementsv 1 Disposed above the lamp bulb is a downwardly i actingsheet-metal reflector 15. This reflector is made out of a single pieceof sheet metal bent to substantially the shape shown. The center of thereflector -is bent down,- asindicated at 26, so as to be close to thelamp'bulb. From this point the I reflector hast/two laterally extendingportions which'extend upwardly and outwardly and then substantiallyhorizontally to the outer portions which are bent downso as to terminateslightly above the level of the top 20 of the lower refiector. The edgesof. the reflector 25 enter into grooves 2'!v formed in laterallyextending screens 28 and 29. These screens are preferably castings andare designed to have the upper contour conform to the shape of thelaterally extending reflectors; 25 and with'the lower edge slightlybelow the top of ,the reflector l8. These screens 28 and 29 have centralportions which are curved inwardly toward the-lamp bulb along agenerally parabolic curve, as indicated at 32. The screens SI OFF-WE! I28 and 29 and the downwardly acting reflector 25,

together with the upwardly acting reflector I8 very completely screenoff the light source so that it will not be seen at ordinary angles ofobservation.

In order to more effectively control the distribution of light laterallyof the luminaire the invention contemplates the use of transverselyextending screens between the depending screens. These transverselyextending screens are received in grooves 33 formed in the castings 28and 29. The screen may, as shown at 34 on the left of Figure 4, extendfrom the upper reflector 25 all the way down to the bottom of the groove33, thereby cutting 01f light from the portion of the reflector 25 tothe left of the screen, or a narrower screen may be used, as indicatedat 35, on the right hand of Figure 4, which permits some light to escapeabove its upper edge for control by the right-hand side of the reflector25, or, as shown in Figure 6, the screen 36 may be much narrower and ofjust suflicient lengthto cut off direct observation of the upper part ofthe lamp bulb from below the lower edge of the reflector 25.

The castings 28 and 29 are provided with pins 31 adapted to enter theholes 22 in the springs 2| so as to support the structure from the lowerreflector and to permit swinging it upwardly as indicated indot-and-dash lines of Figure 4' to facilitate lamp bulb renewal. Spacers38 and screens 39 are employed to hold the parts together.

When the luminaire is placed on the filing cabinet, as indicated in thedrawings, it will be apparent that the eyes of the worker are completelyshielded and the light is not spilled on to the top of the filing casesor in front of the open drawers. The light which strikes the upperreflector 25 will be reflected laterally at wide angles away from nadir,and the quantity of light so emitted will depend upon the portion oflight intercepted by the transverse screens used. The light whichstrikes the side walls of the screens 28 and 29 will be reflected bythem into generally 45 the same direction as the light reflected fromthe upper screen so that there will be a good build up of light atremote points.

Figures 7 and 8 illustrate typical foot candle distribution curves ofillumination obtained from 50 a luminaire such as described employing a100 watt bulb and placed 14" above the working plane. Here the solidline curves 50 and 5011 show the distribution lengthwise of theilluminated area and transversely of the illuminated area ob- 55 tainedwhen both transverse screens are narrow,

as indicated at 36 in Figure 6. When two medium length inserts, such as34, are employed, the distribution is altered to obtain the dottedcurves 5!, Slag It will be apparent that this 60 has built up a higherillumination near the luminaire. When the luminaire employs a wide and anarrow insert one obtains a distribution curve which is indicated by the:rs in the drawings. Part of this curve coincides with the curve 56 andpart with the curve 5!, the intermediate portion 52 being diiferent. Thetransverse distribution is indicated at 52a.

When the screen 34 is used on one side there is a redistribution oflight, depending upon which form of screen is used on the other side,but its principal function is to avoid the possibility of seeing thebright bulb or bright surfaces of reflector 25 at high angles.

When no transverse screens are used there is 75 a build up of light atremote points, but at the hazard of exposing a source of excessivebrightness.

It is obvious that the invention may be embodied in other forms andconstructions within the scope of the claims and I wish it to beunderstood that the particular form shown is but illustrative. Variousmodifications and changes being possible, I do not otherwise limitmyself in anyway with respect thereto except as defined in the claims. a

What is claimed is:

1. A luminaire symmetrical on opposite sides of a median vertical planefor illuminating a long narrow region below the luminaire on oppositesides of said median plane, said luminaire comprising an incandescentlamp bulb disposed over said region and having the light source thereofin said median plane and above the base thereof, a hemisphericalreflector intercepting downwardly directed light and reflecting itupwardly and outwardly, adownwardly acting opaque reflector placedclosely adjacent the upper surface of the bulb and having twodiametrically opposite, laterally extending portions which spread thelight reflected thereby away from the median plane to illuminate themore remote portions of said region and cut off upwardly directed light,and screens extending laterally from said median plane and dependingfromthe said laterally extending portions of the upper reflector and spacedsubstantially the diameter of the hemispherical reflector to preventspread of light laterally of the long narrow area.

2. A luminaire such as claimed in claim 1, having transversely extendingreflecting screens between the laterally extending screens and. underthe upper reflector for screening the upper portion of the light sourceagainst observation at angles near the horizontal and reflecting lightdownwardly.

3. A luminaire such as claimed in claim 1, wherein the screens and upperreflector are detachably supported by the lower reflector.

4. A luminaire such-as claimed in claim 1, wherein the laterallyextending reflectors have straight line sections in planes parallel withthe median plane and the central portions of the vertically extendingscreens are parabolic and reflecting.

5. A luminaire comprising an incandescent lamp bulb with the lightsource thereof above the base, a concentric hemispherical reflectorunder the source, a downwardly acting reflector placed closely adjacentthe upper surface of the bulb, the downwardly actingreflector having twonarrow diametrically opposite, laterally extending portions to spreadthe light reflected thereby into two narrow beams of downwardly andoutwardly directed light substantially 180 apart, and generallyparallel, vertical reflecting screens extending downwardly from theedges of the downwardly acting-reflectors to screen regions between thebeams and of a contour adjacent the bulb to reflect light into the samegeneral radial directions as the light reflected by the downwardlyacting reflectors.

6. A luminaire such as claimed in claim 5, wherein the remote edges ofthe downwardly acting reflectors are slightly above the level of the topof the hemispherical reflector, and the vertical screens extenddown'from the side edges of the downwardly acting reflectors to slightlybelow the level of the top of the hemispherical reflector.

7. A lighting unit for lighting the contents of a row of office filingcases, comprising a base adapted to be placed on top of such a filingcase, an arm secured to the base and extending forwardly and upwardly soas to terminate above and in front of the filing case, a lamp socketcarried on the end of the arm, a lamp bulb in the socket, a reflectingcup under the lamp bulb, diametrically opposite downwardly actingreflectors above the bulb and extending laterally of the bulb fordirecting light away from nadir into two beams of downwardly andoutwardly directed light substantially 180 apart so as to illuminate thecontents of the file drawers of the cases, and substantially verticalgenerally parallel, reflecting screens depending from the side edges ofthe downwardly acting reflectors to cut off light normally emittedforwardly and rearwardly and direct it into the same general directionas the direct light and the light reflected by the downwardly actingreflectors and confine the area of intense illumination to a narrowregion lengthwise of the front wall of the row of filing cases.

8. A lighting unit comprising an upwardly opening, obliquely disposedlamp socket and lamp bulb, a hemispherical reflecting cup about thebulb, narrow screening reflectors disposed in vertical planes andextending generally parallel with one another from opposite sides of thecup, their lower edges being slightly below the top of the cup and theirupper edges being slightly above the top of the bulb, downwardly actingreflectors above the light source and between the upper edges of thescreening reflectors, and obliquely disposed screens extending betweenthe vertical screening reflectors upwardly from points below the levelof the top of the cup.

9. A luminairehaving a light source disposed in an upwardly openingreflecting cup, and a combined reflecting and screening unit detachablysupported above the cup and comprising two generally parallel, verticalside screens having inwardly facing grooves adjacent their upper edges,a downwardly acting reflector fitted in the grooves, and tie rodsextending between the screens and holding the reflector and screenstogether.

10. A luminaire such as claimed in claim 9, wherein the side screenshave other pairs of inwardly facing grooves, and transverse screens aresecured in said grooves.

11. A luminaire having a light source disposed in an upwardly openingreflecting cup, and a combined reflecting and screening unit disposedabove the cup and comprising two generally parallel, vertical sidescreens having inwardly facing grooves adjacent their upper edges, adownwardly acting reflector fitted in the grooves, and

tie rods extending between the screens and'holding the reflector andscreens together, and cupcarried pivot members for supporting the saidunit.

12. A luminaire having a light source disposed in an upwardly openingreflecting cup, and a combined reflecting and screening unit disposedabove the cup and comprising two generally parallel, vertical sidescreens having inwardly facing grooves adjacent their upper edges, adownwardly acting reflector fitted in the grooves, and tie rodsextending between the screens and holding the reflector and screenstogether, and laterally extending springs carried by the cup anddetachably secured to the said unit.

LEROY C. DOANE.

